Wire bonding machines typically include a wire bonding tool, such as a capillary, which receives a metal wire to be bonded by the wire bonding machine. One example of the use of bonded wire is for electrically connecting a semiconductor device (e.g., a die) to a substrate (e.g., a circuit board). In certain wire bonding machines, the capillary is raised and lowered with respect to a work piece by a bond head during the wire bonding process. The vertical motion of the bonding tool also provides access to an end of the wire in a ball-bonding process to form a free-air ball.
Certain conventional wire bonding machines include a tool arm that supports the capillary adjacent one end of the arm. The tool arm is pivotably supported adjacent an opposite end for pivoting about a horizontal axis. The pivoting of the tool arm about the horizontal axis provides the desired vertical (Z-axis) movement of the wire bonding tool. The motion of the tool, however, is along an arc such that it includes both horizontal and vertical components. If linear motion (e.g., vertical only) is desired, the tool arm may be simultaneously translated. The pivoting of the tool arm undesirably causes an associated pivoting of the supported tool. Such tool pivot results in inconsistent looping profiles.
The bondable area for certain conventional wire bonding machines is limited by interference between the work piece and supporting structure for the tool support arm, which is located at or below the location of the tool support arm. The coverage area for such wire bonding machines, therefore, is limited by the length of the tool support arm. The potential reach by the conventional wire bonding machine is sometimes referred to as the “throat” of the machine.
Certain wire bonding machines include a link mechanism for raising and lowering a wire bonding tool with respect to a work piece. The link mechanism includes a tool support member and a pair of arm links pivotably connected to the tool support member and supported from above. The arm links are oblique to each other such that virtual extension lines intersect at a point below the tool support member, thereby minimizing interference to promote increased throat. The motion of the tool support member during the movement of the mechanism, however, includes both horizontal and vertical components. The tool support member is also pivoted during the mechanism movement.
Thus, it would be desirable to provide a wire bonding machine including a mechanism for raising and lowering a wire bonding tool overcoming certain of the deficiencies related to conventional wire bonding machines.